You can run the OS but you can't run anything that a business would use on it (at least not without winning the lottery). Any software package you'll find in the real world is going to be $100k
For learning purposes being able to run zOS would probably be of considerable interest. If the machine actually requires 6 kW to run then I guess the electricity costs would be on the order of $1 per hour, depending on your local rates. Maybe you could set up a service to sell login access.
Note that I'm only speculating here. I'm not a mainframer, just a guy who's had a passing interest in these systems and when I was reading about them it appeared that the difficulty of gaining access to these environments was a significant obstacle to learning about them, whether for professional or hobbyist reasons, that despite the fact that there appears to still be quite a bit of demand for mainframe programmers.
In the USA you'd be able to copy any software available if it was for research, wouldn't you - provided it's also not commercial then there's a strong case for Fair Use exception.
Non-commercial is not an absolute defence not a requirement for Fair Use by it is a factor and with the educational/research facets ...
